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March 8, 1932. L. REICHOLD THERMOSTATIC ELECTRIC SWITCH Filed June 27, 1931 Patented Mar. 8,1932

UNITED; STATES PATENT OFFICE LUDWIG REICEOLD, OF WINSTED, CONNECTICUT, ASSIGNOR TO THE FITZGERALD MANU FAGTURING COMPANY, OF WINSTED, CONNECTICUT, A CORPORATION .OF CONNECTI- OUT Application filed June 27,

ment in obtaining a remote control of the thermostatic switch.

It has heretofore been proposed to provide distant control devices for thermostatic switches, but when such switches are employed with flexible devices such as electric heating pads and the like, the provision of a proper remote control for adjusting the point of cut off of the thermostatic device ofi'ers difiiculties of construction owing to the bulk and the lack of flexibility in the connecting means.

According to the present invention a thermostatic switch is provided with a controlling portion which may be located remotely from the switch proper whereby the switch may be inserted within a heating pad, for example, while the remote control may be secured'at the edge of the pad and project therefrom for easy operation.

One form of construction of the device according to the present invention is set forth on the accompanying drawings, in which:

Figure 1 is a perspective of the switch cas ing and the remote control structure with connecting elements, and showing diagrammatically certain associated features of the heating system.

Figure 2 is a longitudinal sectional view substantially on line 22 of Figure 3.

Figure 3 is a plan view of the device shown in Figure 2, with the upper casing portions removed for exposition of the interiors.

Figure 4 is a detailed sectional view corresponding to Figure 2, but showing the parts in a difierent operative position.

In these drawings, a thermostatic switch casing comprises the bottom wall 10 and an end wall 11 to which is connected a lid 12 having overlapping side flanges 13 for engagement with the side flanges 14 of the bottom member 10, this relationship being assured by the engagement of depressions 15 in these members, for example. The remote control devices comprises a bottom piece 16 and a top piece 17 which may be molded individually of THERMOSTATIC ELECTRIC SWITCH 1931. Serial No. 547,364.

the ends (Figure 3) of a driving chain 23..

It is preferred to provide a resilient friction washer 23a between one portion of the casing and the flange 21 to prevent looseness of the piece 20.

A resiliently flexible connector 24, of spring steel for example, is connected by rivets 25 to the bottom 10 of the switch casing at one end, and is received at its other end between the portions 16, 17 of the remote control casing, being held in position by cut-away portions in this casing structure and by the screw 18. A contact terminal 26 is secured to this spring iece.

p The chain 23 passes through channels 27 formed in the insulating members 16, 17 and then through coil springs 28 which are tightly fitted and clamped between the members 16, 17 and are engaged in nipples 29 formed in the end wall 11 (Figures 2ancl 3). SupportingJ and guiding clamps 24aare provided 1 on the lade 24 to hold the coils 28 in parallel relationship to the blade 24. Within the switch casing, and extending across the central axial plane of the casing, is a stirrup 30 which is secured to the bottom plate 10 and has a threaded opening to receive the externally threaded sleeve 31.- This sleeve 31 has fixedly connected thereto a pair of dished plates 32, 33 which together constitute a drum for the reception of the chain 23, which is secured to the drum by a pin 34. Within the sleeve 31 is threadedly mounted a contact member 35. The bimetallic spring blade 40 extends through the rear end of the switch casing and constitutes a second electrical con- 1 tion; t e current flows through the conduc- 45 v .mately the bimetallic blade is caused to arch bolts 42 which are maintained insulated from it and from the casing. For greater security a sheet 43 of insulatin material such as mica is located above the b ade to prevent contact between it and the drum formed of the members 32, 33. On topof this sheet (Fi 43 is secured a camming piece 45 w ich is engaged by a downwardly projecting portion 33a of the plate 33 (Figure 4) whereby the bimetallic blade 40 is'pushed away from the contact screw 35, whereby to open the circuit, when the drum comprising the plates 32, 33 has been moved to the proper position, corresponding to the indication ofthe pointer 20a 15 of the manual control member 20 opposite the indicia ofi (Fi re 1). The inner end 44 of the bimetallicilade may engage .with the lower end of the terminal screw 35 in Figure 2. 1

As shown in Figure 1 the current supply conductors lead on the one hand to the electrical connecting terminals 40, and on the other hand through the heating resistors 51, 52 and an auxiliary thermostat 53 to the electric connecting terminal 26. It is referred to provide a condenser 54 in shunto the heating elements to prevent deterioration of the contact members.

In operation, the device is located with the switch casing inside of a heating'pad P (Fig: ure 1), and with the manual control member 20 and adjacent portions of the casing projecting therefrom apertures 17a are provided in the parts of the casing so that the edge bindin of the padmay be stitched in positors, the resistor coils 51,52 to ,the terminal 26 and thence to the casing 10 and by brid e 30 to thesleeve 31 and contact screw 35. if the device is cold, the bimetallic blade 40 is in its upper position, and its end 44 is engaged with the contact screw 35 so that the current flows through the blade to the terminal end 40 and thence back to the power line. The resistor coils 51, 52 become heated and ultior bow downward into a position in, which it 3 is free of the contact screw 35. The clrcuit is now 0 en, and the resistor coils 51, 52 deat a temperature determined by the position.

energize so that the pad will cool slightly.-

At a predetermined temperature, contacts 35,

'44 close and the heating begins again. This operation continues and the pad is maintained of the contact screw 35 and the sleeve 31.

It'will be noted that the manual control member 20 extends to both sides of its casing 16, 17, and hence it may be grasped between two fingers and rotated about its axis. By this movement the chain 23 is caused to travel and therewith the drum 32, 33 to be rotated,

5 and. thus the sleeve to be moved'closer to or farther from the position of the blade terminal 44. V In this way the temperature of the cut-ofi may be regulated,and the heatmg manual control member 20 which is located outside of the pad, and also to ositively open the circuit by moving the mem er to tl1e"ofl position. I

The auxiliary thermostat 53 is provided for safety, and is usually set at a slightly higher temperature than the maximum tem perature provided in the controllable thermostat, so that it will open and prevent burning out of the resistors 51, 52 in case the bimetallic blade 40 should have its contact piece 44 frozen to the contact screw 35, or other mechanical injury have occurred. The condenser 54 is provided to decrease the spark at i the opening and closing of the thermostat contacts.

It will be noted that the upper surface of the manually operable piece 20 is provided with a triangular portion 20a which serves both to assist in a proper gripping of the de vice for rotation and as an indicator in con- Junction with the legends on the adjacent portion of the upper piece 17 of the remote control casing.

Owing to the flexible nature of the spring blade 24 and of the coils 28, it will be noted that thepad may yield freely and be caused 2o conform to practically any spatial curvaure.

It is obvious that the invention is not limited to the form of construction shown, but that may be modified in many ways within the scope of the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is

1. A thermostatic electricswitch'comprismg a thermostatically actuated movable contact and a cooperating contact, means for 'moving said relatively fixed contact toward and from said movable contact, an adjusting device located remote from said contacts, a

flexibleconnection between said means and said device for operating said means, and

flexible mechanical connecting means associating said contacts and saiddevice.

2. A thermostatic electric switch comprising a thermostatically actuated movable contact and a cooperating contact, means for regulating the relative positions of said contacts Q id block, and a driving connection guidedl held to said link between said piece and said means for operating the latter.

3. A thermostatic electric switch comprising a switch casing adapted to be inserted in a heating pad or like structure, a thermostatically actuated and a cooperating contact in said casing, means to adjust said contacts relative to one another, a control casing adapted to be fixed to the pad and project in part therefrom, a flexible link connecting said switch and control casings, a regulating piece in said control casing, and a driving connection guidedly held to said link between said piece and said means.

4. A thermostatic electric switch comprising a switch casing, a thermostatically actuated contact in said casing, a cooperating contact having a screw-threaded mounting in said casing, a control casing, a manually rotatable control piece in said control casing, a flexible link for mechanically connecting said casing, a driving chain for connecting said piece and said fixed contact whereby to rotate the latter in its mounting and thereby adjust the same relative to said actuated contact, and means connected to said link for guidedly holding said driving chain.

, 5. A thermostatic electric switch comprising a switch casing, a thermostatically actuated contact in said casing, a cooperating contact, revoluble means for adjusting the contacts with respect to one another, a control casing, a flexible link for connecting said casings, a manually rotatable piece in said control casing, an endless chain for connecting said piece and said means for simultaneous movement, and tubular flexible guards surrounding portions of said chain external to said casings and connected to said link.

' 6. A switch as in claim 5, in which the guards are helical springs, and said link has portions for holding said springs.

7. A switch as in claim 5, in which the guards are helical springs having their ends engaged in said casings, and means are rovided on said link for embracing and hol ing said springs to said link.

8. A thermostatic electric switch comprising a switch casing, a thermostatically actuated contact in said casing, a cooperating contact in said casing, means for adjusting the relative position of said contacts includ ing a screw-threaded member, a drum on said member, a control casing, a revoluble regulat ing piece in said control casing, a flexible link for connecting said casings, and a driving chain connected to both said piece and said means for causing simultaneous movement thereof and guidedly held by said link.

9. A thermostatic electric switch comprising a switch casing, a thermostatically actuated contact in said casing, a cooperating contact, revoluble means for adjusting the contacts with respect to one another, a control casing, a manually rotatable control piece in contact, a control casing, a manually rotatable control piece in said control casing, means on said drum and insulated from said thermostatically actuated contact for positively moving said thermostatically actuated contact out of engagement with said cooperating contact in one position of said drum, and a driving chain for connecting said piece and said drum whereby to rotate the latter and therewith adjust said cooperating contact with respect to said actuated contact and also to engage said means with said actuated contact in one position of said arts whereby to positively open the circuit through the switch.

In testimony whereof I afiix my signature.

LUDWIG REICHOLD. 

